As a result of the decrease in the availability of inexpensive fertile farm land proximate to population centers, the increasing scarcity of water and the increasing need to find economical means of producing food to feed world population growth, the interest in vertical hydroponic growing systems has dramatically increased over the previous four decades and there presently exists many known variations, including apparatuses for commercial and home applications. Hydroponic systems are often referred to by referencing the plant root mass fertigation method used. The three variations briefly described below are all known to make use of root system containment apparatus generally known as grow tubes, which are hollow, elongated cylindrical bodies often constructed of thermoplastic material such as PVC, that are configured to hold a multitude of plants and therefore have particular relevance to the present invention:
1. Media-ponic growing systems, utilizing artificial soil, also known as substrate or grow media, in which plants are rooted, usually utilize a mixture of organic (primary component) and inorganic materials (secondary component) substituting for natural traditional soil mixtures, and
2. Aqua-ponic growing systems, with plants rooted in liquid nutrient directly, without use of substrate and relying upon direct application of liquid nutrient to plant roots by continuous emersion or by continuous contact with a film-flow or by alternatively flooding and draining, and
3. Aero-ponic growing systems, with plants rooted in air, without use of grow media and involving spraying of plant roots with a liquid nutrient aerosol within a spray chamber.
The present invention primarily represents advancement in the design of the 100% in-organic substrate-based media-ponic variation of vertical hydroponic agriculture growing systems including improvements in grow tube apparatus structure and substrate BSO ecology, grow tube fertigation systems and related modular greenhouse enclosures. Its purpose is to address a number of the previously known operational disadvantages of substrate-based growing and fertigation systems to improve their efficiency, productivity, cultivation of beneficial soil organisms, capacity for pathogen suppression, modularity and ability to be mass-produced, to accommodate optional overhead conveyor operation and to be used with modularized transportable greenhouse enclosures.
Following are examples of such known disadvantages:
1. Vertical plant container designs are most often freestanding floor supported structures focused on the growing system aspect and not configured in modular, adjustable, easily demountable and adaptable arrangements that use readily available affordable materials, that facilitate manufacture, transport, installation, maintenance, disassembly, rearrangement, and application to the widest possible variety of plants, crops and growing conditions.
2. Such vertical grow system designs may be used in greenhouse enclosures, but are not usually specifically configured to integrate with modularized, transportable portable greenhouse structures, or to permit the optional use of overhead conveyor systems in production. Floor supported designs also provide more convenient points of access for crawling pests.
3. The weight of known grow tubes combined with the dampened weight and volume of commonly used substrate mixtures of primarily organic and secondarily inorganic grow media can limit vertical growing system heights and plant quantities per unit of ground area due to overall apparatus size, weight and container cultivation, portability and accessibility issues.
4. High per-unit manufacturing, installation and maintenance costs are often required due to the complexity of custom vertical plant container designs. Additionally, custom components are often not readily available or available at an affordable cost to all potential growers.
5. Known grow tube designs are often seen as being suitable for growth of organic produce while utilizing construction materials for grow tubes, piping and fittings that are not certified as suitable for use in potable water systems (“PW” certified), that is to say, over time some of the materials most often used may leach chemicals into the nutrient stream at concentrations considered to be above safe limits.
6. Except for seed germination substrate and some ground supported “lay-flat” media filled growing bags, which may utilize 100% light-weight granular inorganic grow media such as perlite (expanded volcanic glass granules), the plant support grow media most commonly used is a mix of primarily organic and secondarily in-organic materials. The source of its organic components and the relatively large volume of substrate used for each plant can lead to conditions that support pathogen contamination and/or an undesirable imbalance of air and moisture, mineral salts, electrical conductivity and/or a pH imbalance. “Lay-flat bags are typically one crop cycle containers that are sterilized for re-use each growing cycle or discarded and do not provide an optimal, stable container ecology for the cultivation of beneficial soil organisms and pathogen suppression. Another related source of pathogen contamination can be the introduction of starter plants having been grown in soil.
7. Grow media compaction resulting from primarily organic and secondarily inorganic mix proportions and excessive root growth can occur in commonly used substrate, leading to over-saturation and lack of sufficient air within the mixture when the media volume and composition restricts efficient nutrient drainage and flow uniformity, thereby affecting plant and health and requiring expensive and frequent grow media replacement or sterilization to avoid contamination of subsequent crops.
8. Use of a closed-loop fertigation and recycling system can facilitate spread of plant diseases when excessive quantities are circulated, or when the distribution system has an excessive number of open nutrient emitter points such as at each plant grow-site, thereby multiplying potential points of entry for pests and pathogens or when the substrate retains an excessive amount of liquid nutrient between fertigation applications, or when the fertigation temperature is allowed to increase or when the recycling system does not include sufficient filtering, monitoring, analysis and adjustment to foster an optimal grow tube ecology and to counter pathogen growth and debilitating nutrient imbalances.
Use of an excessive number of nutrient emitter points and use of conventional pressure regulating drip emitters can result in maintenance and operational inefficiencies due to clogging of emitters.
As a result of these and other factors, some commercial substrate-based growing systems presently in use have limited their application to high value vining plants such as tomatoes or cucumbers that allow for a reduction of the number of substrate container grow-sites in a vertical column to one or a few. Also due to the above cited disadvantages, many commercial hydroponic growers have become focused on non-substrate-based hydroponic growing systems such as aqua-ponics and aero-ponics. Although some of the substrate-based system disadvantages noted above are mitigated by non-media based systems, others remain and new disadvantages arise; for example:
1. A relatively high level of grower skill, technology and operational knowledge is required for aqua-ponic and aero-ponic agriculture systems operation, limiting their use in underdeveloped regions.
2. Vertical system heights, use of overhead support configurations or overhead conveyance means can be constrained due to apparatus and liquid nutrient weight, thereby limiting plant densities and system adaptability.
3. A relatively high per unit cost is required for manufacturing, transport, installation, operation and maintenance due to the specialized apparatus and continuous operation of the liquid nutrient movement, containment and delivery systems. These higher per unit costs can effectively reduce the net benefit of the extremely high plant densities claimed by some systems.
4. Because of the closed loop aspect of continuous fertigation operations, disassembly and demounting of individual grow tubes and isolated component parts can be impeded.
5. High operational water quantities and continuous operation are required to avoid plant dehydration, resulting in increased energy consumption, excessive loss to evaporation and maintenance for the fertigation system. Use of a common liquid nutrient and constant recycling, combined with the large volumes of liquid nutrient required, can facilitate spread of plant diseases and algae growth. Relatively large quantities of spent nutrient are also created that must be recycled, monitored, adjusted for reuse and ultimately disposed of as waste product. The soil-less environment can support some beneficial microbial culture, but is not an optimal environment and can impede establishment of beneficial organism dominance and suppression of pathogen development.
6. With respect to aero-ponic systems, clogging of fertigation spray nozzles can reduce overall efficiency and increase maintenance costs.
7. Because of the relatively high cost of apparatus and high level of operating water usage, many of the known aqua-ponic and aero-ponic vertical hydroponic growing systems have been created primarily for home use rather than for commercial use in order to command higher purchase prices, thereby limiting the value of features they may possess to commercial growers or to less affluent growers.
Examples of growing systems in this area are disclosed in the following U.S. Pat. Nos. 4,255,896; 4,454,684; 4,986,027; 5,428,922; 5,555,676; 6,408,570; 6,840,008; 6,928,772; 8,065,833; 8,225,549; 8,250,809; 8,291,641; and 2013/0067813. Various drawbacks are presented by the prior systems, primarily their high cost and unsuitability to implement on a large commercial scale, but also their lack of focus on the creation of a growing environment suitable for cultivation of beneficial soil organisms as well as plants, lack of structural means to control the balance of air and water in the substrate, inefficient use of liquid nutrient fertigation, excessive weight, lack of mobility, lack of adaptability and flexibility to enable reconfiguration for differing greenhouse configurations, plant types, climates, grower and market needs.
Examples of growing systems in this area are also disclosed in the following Publications: (1) Ziegler, L. R., Synergy International, Inc. (Copyright 2009) published on the internet as “The Vertical Aeroponic Growing System,” 18 pages—Discloses an aero-ponic growing system, with the most relevant embodiment comprised of modular stacked, cylindrical ceramic plant holding pots. The disclosed ceramic pots with vertical rotation and floor-mounted support frames would have limited flexibility for reconfiguration, be heavy and relatively expensive to construct, and result in a high cost per vertical grow-column unit; (2) Disneyland Epcot Center Hydroponics Greenhouses, Orlando, Fla., available for public tours and published on multiple internet sites, including <thephotogardenbee.com/2010/01/05/aeroponics-gardens-at-epcot-part-iii-the-land/>, discloses large diameter hollow vertical PVC “column pots,” used for a hydroponics exhibiting rather than for commercial growing, suspended from overhead conveyor tracks and provided with an internal aeroponic spray fertigation system with waste discharged on the ground.
Consequently, there is a need for a vertical hydroponic growing system that is designed for both cultivation of plants and BSO's, that can easily be scaled up or scaled down in size, is highly resource efficient, is suitable for mass-production, is constructed of readily available and affordable components, including light-weight, potable water safe materials such as thin-wall, potable water (PW) certified PVC, can be readily and reliably reconfigured for multiple uses, is compatible with contemporary and emerging organic agricultural practices, fixed or overhead conveyor operations and integrates easily with conventional, modularized or transportable, modularized greenhouse enclosures.